PT  - JOURNAL ARTICLE
AU  - Andrew Goudie
AU  - Pippa Hopkinson
AU  - Brian Lipworth
AU  - Allan Struthers
TI  - Acute and chronic effects of PDE5-Is on SpO2 in patients with COPD associated pulmonary hypertension
DP  - 2013 Sep 01
TA  - European Respiratory Journal
PG  - P4071
VI  - 42
IP  - Suppl 57
4099  - http://erj.ersjournals.com/content/42/Suppl_57/P4071.short
4100  - http://erj.ersjournals.com/content/42/Suppl_57/P4071.full
SO  - Eur Respir J2013 Sep 01; 42
AB  - BackgroundPulmonary hypertension as a complication of COPD negatively influences important outcomes such as mortality, hospitalisation and exercise capacity. The use of PDE5-Is to treat PH in this patient group is currently being explored but concerns persist regarding PDE5-I induced V/Q mismatch as occurs with Bosentan.AimsTo determine the acute and chronic effects of PDE5-Is on SpO2 in patients with COPD-PHMethodsResults from the 3P trial were used, comprised of patients with moderate-severe COPD and echo defined PH. A single dose of sildenafil 50mg was given to 120 patients. Resting SpO2 was recorded at 0,30,60,120,180mins. All patients had read an information leaflet stating common SEs and were asked to report any. Resting SpO2 was also assessed in the main study cohort at 0 and 12 weeks following once daily tadalafil 10mg or matched placebo (60 per arm).ResultsThe figure shows sildenafil's acute effects on SpO2 over time.One patient (0.8%) felt increased breathlessness. Two patients (1.7%) felt less breathless. SpO2 did not however change significantly between active/placebo groups following 12 weeks of daily tadalafil, mean Δ -0.91% and -0.70% respectively (p=0.543).ConclusionsSignificant SpO2 changes during acute sildenafil dosing strongly suggest transient asymptomatic V/Q mismatch. Chronic daily tadalafil dosing had no significant effect on SpO2 suggesting that significant V/Q mismatch did not occur.